might behave differently when more numerous; but Mr. Smith informs me that
he has watched the nests at various hours during May, June and August, both
in Surrey and Hampshire, and has never seen the slaves, though present in
large numbers in August, either leave or enter the nest. Hence, he
considers them as strictly household slaves. The masters, on the other
hand, may be constantly seen bringing in materials for the nest, and food
of all kinds. During the year 1860, however, in the month of July, I came
across a community with an unusually large stock of slaves, and I observed
a few slaves mingled with their masters leaving the nest, and marching
along the same road to a tall Scotch-fir tree, twenty-five yards distant,
which they ascended together, probably in search of aphides or cocci.
According to Huber, who had ample opportunities for observation, the slaves
in Switzerland habitually work with their masters in making the nest, and
they alone open and close the doors in the morning and evening; and, as
Huber expressly states, their principal office is to search for aphides.
This difference in the usual habits of the masters and slaves in the two
countries, probably depends merely on the slaves being captured in greater
numbers in Switzerland than in England.

One day I fortunately witnessed a migration of F. sanguinea from one nest
to another, and it was a most interesting spectacle to behold the masters
carefully carrying their slaves in their jaws instead of being carried by
them, as in the case of F. rufescens. Another day my attention was struck
by about a score of the slave-makers haunting the same spot, and evidently
not in search of food; they approached and were vigorously repulsed by an
independent community of the slave species (F. fusca); sometimes as many as
three of these ants clinging to the legs of the slave-making F. sanguinea.
The latter ruthlessly killed their small opponents and carried their dead
bodies as food to their nest, twenty-nine yards distant; but they were
prevented from getting any pupae to rear as slaves. I then dug up a small